How To sand or treat a large area of old thinset from a concrete slab

Connie Thomas
by Connie Thomas
the foyer is on an 18” deep concrete slab old tiles have been removed ( circa 1972) leaving very rough thinset marks as well as gouges trying to pry up the tiles
we are living in house and all equipment to sand with diamond pads appears to create so much grit it will be impossible To do
is there anything liquid that can be put down to “eat at “the thinset making chiseling an easier job. goal is to polish concrete base and leave natural
  7 answers
  • GrandmasHouseDIY GrandmasHouseDIY on Jun 22, 2018

    Oh Connie, I am SO sorry, my only advice is exactly what you said you feel you cannot have done. Concrete/thinset/mortar is VERY tough stuff - you will have to grind/sand it off of there as far as I know.

  • Karen George Karen George on Jun 23, 2018

    Not sure if this would work but have you considered putting a layer of cement on top and smoothing? Like filling holes in your wall.

    • Connie Thomas Connie Thomas on Jun 25, 2018

      Was told that doesn’t work and do not have the space but believe the thin set still must be removed first

  • Pat Guillen Pat Guillen on Jun 23, 2018

    There is actually a scrapper that is specifically made to scrape all that off. I am not going to say it's easy, but it beats getting down on your knees or all the dust grinding/sanding will create.

    • See 1 previous
    • Pat Guillen Pat Guillen on Jun 25, 2018

      Yeah, the scraper does take chunks of concrete but if you are going to lay tile again you can level the floor with the new thinset. They also rent electric scrapers (Ace), or a floor maintainer. Looks sort of like a buffer, and it grinds awy the thin set but you will get a lot of sand with that.

  • Frank Frank on Jun 23, 2018

    Why not use self leveling floor level and tint it to the color you want if your goal is to have polished concrete

  • Joh14316485 Joh14316485 on Jun 24, 2018

    Home depot has a Mortar Dissolver

  • Connie Thomas Connie Thomas on Jun 25, 2018

    on my way I’ll try anything

  • William William on Jul 13, 2018

    Scraping off with an Ice scrape is what i have always done. Then use a cement floor leveling compound to smooth out the concrete.